Question

A colleague once said that God is killing a kitten every time I write a for-loop.

When asked how to avoid for-loops, his answer was to use a functional language. However, if you are stuck with a non-functional language, say C#, what techniques are there to avoid for-loops or to get rid of them by refactoring? With lambda expressions and LINQ perhaps? If so, how?

Questions

So the question boils down to:

1. Why are for-loops bad? Or, in what context are for-loops to avoid and why?
2. Can you provide C# code examples of how it looks before, i.e. with a loop, and afterwards without a loop?

Answer 1

Functional constructs often express your intent more clearly than for-loops in cases where you operate on some data set and want to transform, filter or aggregate the elements.

Loops are very appropriate when you want to repeatedly execute some action.

---

For example

int x = array.Sum();

much more clearly expresses your intent than

int x = 0;
for (int i = 0; i < array.Length; i++)
{
    x += array[i];
}